High-power rocketry is a hobby similar to model rocketry. The major difference is that higher impulse range motors are used. The National Fire Protection Association (NFPA) definition of a high-power rocket is one that has a total weight of more than 1500 grams and contains a motor or motors containing more than 62.5 grams of propellant or rated at more than 160 Newton-seconds of total impulse.

High-power rockets are defined as rockets flown using commercially-available motors ranging from H to O class. In the U.S., the NFPA1122 standard dictates guidelines for model rocketry, while NFPA1127 is specific to high-power rockets. In most U.S. states NFPA1122 has been adopted as part of the legal code. A smaller number of states use NFPA1127

Unlike model rocketry, certification is required by the governing organizations in order for individuals to fly high powered rockets.The certification system is standardized across the hobby and governing organizations. There are three levels of certification, each allowing the user to fly successively larger motors. In the USA (TRA and NAR):

Level 1: H, I

Level 2: J, K, L

Level 3: M, N, O and beyond

In order to gain certification an individual needs to demonstrate his ability to fly a rocket within the given power range of the level he is seeking successfully. For example, if an individual desires to gain a Level 1 certification he must successfully fly a H-I motor in an appropriately sized rocket. This is also true for Level 2 and 3 certification with the added requirements that, for Level 2 a test be successfully passed and for Level 3 the build be documented and overseen by an individual that is already of Level 3 certification, and authorized by the respective organization. These requirements vary slightly between NAR and Tripoli, but are very close in both organizations.

High-power rocket designs can vary widely as do anticipated altitudes and performance but altitudes of 10,000 ft and velocities in the supersonic ranges are not uncommon. A combination of (often) larger mass and higher apogees may require sophisticated recovery systems. High-power rockets are frequently flown with sophisticated electronic devices used for recording flight data (altitude, velocity, acceleration/deceleration, G-forces) and for deploying recovery methods or devices.

High-power rockets are constructed from materials such as phenolic resin, fiberglass, carbon fiber, and other composite materials and plastics. Motor casings are normally machined aluminium with ablative phenolic or paper liners and are reloadable, i.e. can be used multiple times.

High-power rockets are predominantly powered by commercially-available APCP-based motors or nitrous oxide-based hybrid motors. Experimental Propulsion is also the source of propulsion for many high-power rockets.

Motors for High-Power Rocketry are "H" and above. The lettered naming system is a standard in the hobby in which successive letters double the delivered impulse of the previous letter. Each letter also has a range of impulses under which a given motor can be classified.